An I-Team review of school budgets found the average portable trailer costs taxpayers $60,000 – still less expensive than building new schools.

"We just can't add space fast enough to keep up with the growth,” said Dana Tofig of Montgomery County Public Schools. “So portables are a reality. They've been around for a while. They'll probably be around for a while."

With 2,500 new kids in Montgomery County each year, they would need four new buildings just to keep up with the growth.